Since the 1930's, the Foley drainage catheter has remained the preferred option for patients requiring urinary diversion. The basic design of one or more drainage ports at or near the distal end, a central drainage lumen, an elastomeric retention balloon for anchoring the catheter in the bladder, and a proximally-located valve to keep the fluid from leaking out the inflation lumen and deflating the balloon, has not undergone significant evolution other than the change from latex to silicone.
The Foley catheter does have some acknowledged weaknesses. Chief among them is displacement of the catheter due to accidental or intentional dislodgement from the bladder, which may be attributed to the patient pulling on the proximal exposed portion. There is much greater risk of dislodgement if the balloon has partially or fully deflated due to a leak at the proximal valve or balloon itself, or due to the natural diffusion of the balloon contents over time through a semi-permeable balloon material.
While dislodgement of a Foley catheter is not usually serious in most instances, it can be a very large problem in patients who have undergone a radical prostatectomy where the prostate has been removed and the urethra resectioned. The standard procedure for prostatectomy patients is to place a Foley drainage catheter at the time of surgery to be left in place for no more than two to three weeks. Besides providing drainage, the catheter keeps the anastomotic site patent during the healing process and offers some degree of protection from strain and trauma. If the catheter is dislodged, however, it can damage the delicate anastomotic site, especially early in the post-surgical recovery period. Even if the sutures at the site do not pull out during dislodgement, the surgeon may be forced to reopen the patient to place another drainage catheter to prevent possible damage during its introduction through the surgical resection site.
Given the seriousness of having a Foley drainage catheter dislodge following a surgical procedure such as a radical prostatectomy, there is a strong need for a catheter design that helps preclude the balloon or retention member from displacing and causing damage to the surgical site. Existing devices do not provide this important safety feature of retaining the catheter inside the bladder.
In addition to the Foley catheter for urinary drainage, there are catheters used in gastric, vascular, and other procedures that utilize a balloon or other means for retention, occlusion or dilatation in which deflation or a related failure could be critical.